exo::CompositorFrameSinkHolder's release callbacks hold ref

components/exo/buffer.cc

Index: components/exo/buffer.cc
diff --git a/components/exo/buffer.cc b/components/exo/buffer.cc
index 9b1778d989d6c0250efff832d6372f401e15e129..8c5ac5dbfc60871e652474da22b5d784697b2f8f 100644
--- a/components/exo/buffer.cc
+++ b/components/exo/buffer.cc
@@ -24,6 +24,7 @@
 #include "cc/output/context_provider.h"
 #include "cc/resources/single_release_callback.h"
 #include "cc/resources/texture_mailbox.h"
+#include "components/exo/compositor_frame_sink_holder.h"
 #include "gpu/command_buffer/client/context_support.h"
 #include "gpu/command_buffer/client/gles2_interface.h"
 #include "ui/aura/env.h"
@@ -398,10 +399,12 @@ Buffer::Buffer(std::unique_ptr<gfx::GpuMemoryBuffer> gpu_memory_buffer,
 
 Buffer::~Buffer() {}
 
-std::unique_ptr<cc::SingleReleaseCallback> Buffer::ProduceTextureMailbox(
-    cc::TextureMailbox* texture_mailbox,
+bool Buffer::ProduceTransferableResource(
+    CompositorFrameSinkHolder* compositor_frame_sink_holder,
+    cc::ResourceId resource_id,
     bool secure_output_only,
-    bool client_usage) {
+    bool client_usage,
+    cc::TransferableResource* resource) {
   DCHECK(attach_count_);
   DLOG_IF(WARNING, use_count_ && client_usage)
       << "Producing a texture mailbox for a buffer that has not been released";
@@ -433,9 +436,20 @@ std::unique_ptr<cc::SingleReleaseCallback> Buffer::ProduceTextureMailbox(
   if (!context_provider) {
     DLOG(WARNING) << "Failed to acquire a context provider";
     Release();  // Decrements the use count
-    return nullptr;
+    resource->id = 0;
+    resource->size = gfx::Size();
+    return false;
   }
 
+  // The reference to the CompositorFrameSinkHolder keeps it alive until a
+  // release callback is received.
+  compositor_frame_sink_holder_ = compositor_frame_sink_holder;
+
+  resource->id = resource_id;
+  resource->format = cc::RGBA_8888;
+  resource->filter = GL_LINEAR;
+  resource->size = gpu_memory_buffer_->GetSize();
+
   // Create a new image texture for |gpu_memory_buffer_| with |texture_target_|
   // if one doesn't already exist. The contents of this buffer are copied to
   // |texture| using a call to CopyTexImage.
@@ -450,18 +464,19 @@ std::unique_ptr<cc::SingleReleaseCallback> Buffer::ProduceTextureMailbox(
     Texture* texture = contents_texture_.get();
 
     // This binds the latest contents of this buffer to |texture|.
-    gpu::SyncToken sync_token = texture->BindTexImage();
+    resource->mailbox_holder = gpu::MailboxHolder(
+        texture->mailbox(), texture->BindTexImage(), texture_target_);
+
+    resource->is_overlay_candidate = is_overlay_candidate_;
 
-    *texture_mailbox =
-        cc::TextureMailbox(texture->mailbox(), sync_token, texture_target_,
-                           gpu_memory_buffer_->GetSize(), is_overlay_candidate_,
-                           secure_output_only);
     // The contents texture will be released when no longer used by the
     // compositor.
-    return cc::SingleReleaseCallback::Create(
+    compositor_frame_sink_holder_->SetResourceReleaseCallback(
+        resource_id,
         base::Bind(&Buffer::Texture::ReleaseTexImage, base::Unretained(texture),
                    base::Bind(&Buffer::ReleaseContentsTexture, AsWeakPtr(),
                               base::Passed(&contents_texture_))));
+    return true;
   }
 
   // Create a mailbox texture that we copy the buffer contents to.
@@ -476,19 +491,22 @@ std::unique_ptr<cc::SingleReleaseCallback> Buffer::ProduceTextureMailbox(
   Texture* texture = texture_.get();
 
   // The contents texture will be released when copy has completed.
-  gpu::SyncToken sync_token = contents_texture->CopyTexImage(
-      texture, base::Bind(&Buffer::ReleaseContentsTexture, AsWeakPtr(),
-                          base::Passed(&contents_texture_)));
-  *texture_mailbox =
-      cc::TextureMailbox(texture->mailbox(), sync_token, GL_TEXTURE_2D,
-                         gpu_memory_buffer_->GetSize(),
-                         false /* is_overlay_candidate */, secure_output_only);
+  resource->mailbox_holder = gpu::MailboxHolder(
+      texture->mailbox(),
+      contents_texture->CopyTexImage(
+          texture, base::Bind(&Buffer::ReleaseContentsTexture, AsWeakPtr(),
+                              base::Passed(&contents_texture_))),
+      GL_TEXTURE_2D);
+  resource->is_overlay_candidate = false;
+
   // The mailbox texture will be released when no longer used by the
   // compositor.
-  return cc::SingleReleaseCallback::Create(
+  compositor_frame_sink_holder_->SetResourceReleaseCallback(
+      resource_id,
       base::Bind(&Buffer::Texture::Release, base::Unretained(texture),
                  base::Bind(&Buffer::ReleaseTexture, AsWeakPtr(),
                             base::Passed(&texture_))));
+  return true;
 }
 
 void Buffer::OnAttach() {
@@ -534,17 +552,21 @@ void Buffer::CheckReleaseCallback() {
   // Run release callback to notify the client that buffer has been released.
   if (!release_callback_.is_null())
     release_callback_.Run();
+
+  compositor_frame_sink_holder_ = nullptr;
 }
 
 void Buffer::ReleaseTexture(std::unique_ptr<Texture> texture) {
-  texture_ = std::move(texture);
+  if (this)

[reveman, 2017/01/03 23:24:46]

remove "if (this)". that's never a good idea and the call to this function is
already protected by a weak ptr. 

[Alex Z., 2017/01/03 23:39:15]

Done.

+    texture_ = std::move(texture);
 }
 
 void Buffer::ReleaseContentsTexture(std::unique_ptr<Texture> texture) {
   TRACE_EVENT0("exo", "Buffer::ReleaseContentsTexture");
-
-  contents_texture_ = std::move(texture);
-  Release();
+  if (this) {

[reveman, 2017/01/03 23:24:46]

ditto

[Alex Z., 2017/01/03 23:39:15]

Done.

+    contents_texture_ = std::move(texture);
+    Release();
+  }
 }
 
 }  // namespace exo